In situations of intensively accelerated development of the performance and functions of control target appliances, microcomputers incorporated in electronic control devices for controlling the appliances have improved in performance year by year.
For example, for electronic control devices such as electronic control units for controlling engines of vehicles, in the midst of the accelerated development of the performance and functions of the engines, new types of application software (control logics) have been developed in advance considering electronic control devices of the next generation exhibiting superior performance to the performance of the existing electronic control devices.
The control logics developed in advance target, in many cases, microcomputers of the next generation that are expected to improve in performance. However, there are cases where no electronic control devices exist incorporating such microcomputers with improved performance at the time of development of the control logics, and even cases where the microcomputers of the next generation themselves do not exist. Thus, in many cases, there was no way but to develop advanced logics on the basis of the existing microcomputers.
However, in the cases of developing the advanced logics using electronic control devices incorporating the existing microcomputers, problems arise including deficiencies in processability of CPUs of the microcomputers, deficiencies in memory capacity, and further, deficiencies in peripheral resources, making development of highly accurate advanced logics difficult. This has caused hindrances to development of new products, including a delay in development of application software that corresponds to the microcomputers of the next generation.
That is, the microcomputers incorporated in the existing electronic control devices are such that in order to minimize the cost associated with the electronic control devices, CPU performance and peripheral resources are selected to secure optimum specifications for existing systems and then incorporated into a single package. This fails to deal with the need for making changes in the performance and functions when attempting to correspond to new products, unless the microcomputers themselves are changed.
In view of this, patent document 1 proposes a software developing device including three functional blocks: a central block including an application processing function portion that simulates a CPU built in a microcomputer and a communication function portion; a peripheral block connected to the central block through a PCI bus; and an interface circuit block connected to the peripheral block.
The peripheral block includes a simulation microcomputer peripheral device that carries out input-output processing through implementing, on software, a peripheral resource built in the microcomputer, an operation function portion, and a communication function portion. The interface circuit block includes a circuit that is equivalent to hardware other than the microcomputer incorporated in an electronic control unit.
The operation function portion of the peripheral block is provided with a bus controller; the communication function portion of the central block and the bus controller are connected to one another through the PCI bus; and the bus controller and the simulation microcomputer peripheral device are connected to one another through an internal bus, to result in such a configuration that data is transmitted-received between the communication function portion and the simulation microcomputer peripheral device through the PCI bus, the bus controller, and the internal bus.
Referring to FIGS. 2B and 7, this software developing device is such that the central block has mounted thereon an IO driver that serves as software for implementing a function equivalent to a bus connected to an internal resource of the microcomputer, that the central block and the peripheral block are connected to one another through the PCI bus, that the central block has mounted thereon a platform that serves as software for connecting the IO driver and application software to one another, and that the peripheral block has mounted thereon a simulation microcomputer peripheral device composed of FPGA as firmware.    [Patent document 1] Japanese Unexamined Patent Publication No. 2004-234530.